1. Field of Invention
The present invention is generally related to a shredder having at least one light-emitting diode (LED) acting as an emitter and detector to assist in determining an operation of cutter elements for shredding articles.
2. Background
A common type of shredder has a shredder mechanism contained within a housing and mounted atop a container. The shredder mechanism typically includes a cutting head assembly including a series of cutter elements that shred articles such as paper, CDs, DVDs, credit cards, and the like that are fed therein and discharge the shredded articles downwardly into the container. An example of such a shredder may be found, for example, in U.S. Pat. No. 7,040,559, which is herein incorporated by reference in its entirety.
When users feed articles into the shredder mechanism, a sensor may be provided to detect the presence of such articles, thereby activating the shredder mechanism to shred the articles. One or more sensors may also be provided to detect if the container is full of shredded articles. Optical sensors are commonly used because they have no moving parts. However, the optical sensors used in shredders preferably have a wide range of electrical characteristics and/or sensitivities to detect the wide range of articles and media (e.g., articles of various colors, materials), without providing any false positive signals for activating the shredder mechanism during the life of the sensor. For example, the drive signal of the sensor must provide an intensity of light that is sensitive to detect both paper and CDs and/or shredded articles.
Typical examples of optical sensors include those which have discrete components for emitting and for detecting light or radiation, such as an infrared (IR) beam. Such sensors require that the beam be interrupted (i.e., broken) between the emitter and detector to sense a condition. Alternatively, reflective-types sensors may be used (e.g., which detect reflected light or beams), which may use a simple assembly rather than discrete components. However, improvements in cost, assembly, and construction of sensors that are used in shredders would be beneficial.